This invention relates to improvements in an inplace gasket belling machine and more particularly to improved means for supporting a pipe in the machine, improved means for heating one end portion of the pipe, an improved belling mandrel and means for automatically placing a gasket on the belling mandrel.
Presently known inplace gasket belling machines have several shortcomings which are resolved by the improvements of the present invention. Generally, the pipe end portion to be belled is heated by standing the pipe on end and immersing the end portion into a bath of heated fluid. Problems associated with this method of heating are first, that substantial vertical clearance is required for standing the pipes on end and second, that the entire end portion of the pipe is heated to a generally uniform temperature so that a substantial temperature interface is formed between the immersed and non-immersed portions. The sudden temperature change along the pipe increases the chances of the end portion being axially collapsed during insertion of the belling mandrel.
A related problem associated with the immersion type heating of the pipe end portion is that somewhat complex pipe handling apparatus has been required for supporting the pipe in perpendicularly related heating and belling positions.
It has generally been the practice to manually place gaskets on the belling mandrel in order to provide clearance for passage of the mandrel into the heated end portion of a pipe. This operation thus necessitates operator assistance with the belling of each pipe.
Conventional inplace gasket belling machines have heretofore employed a fixed mandrel and a single speed drive means for advancing the mandrel into one end of a pipe. The speed of the drive means is generally a compromise between a relatively fast speed conducive to expanding the pipe end portion and a slow speed conducive to accurate depth control of the mandrel within the pipe. Furthermore, it has been necessary to provide independent drive means for a gasket positioning sleeve on the mandrel because of the required axial movement of the sleeve relative to the mandrel during the belling operation.
It is believed that all of the above-mentioned shortcomings are resolved by the improved inplace gasket belling machine of the present invention.